A Government Accountability Office report singled out amphibious ships as having more material problems than surface combatants — problems that could hurt readiness. Here, a sailor repairs a weld aboard the amphibious transport dock Denver. (MC1 David R. Krigbaum / Navy)

The fleet recently adopted a rigorous plan to train and maintain ships. But, as congressional watchdogs have asked, what happens if the Navy doesn't follow it?

This is not a rhetorical question. Deployments are stretching the fleet. The Eisenhower Strike Group, one of four carrier groups deployed as of Oct. 5, is on a nine-month deployment, one of the longest for a CSG in a decade. The destroyer Paul Hamilton left Pearl Harbor in late September on what's scheduled to be a 10-month cruise.

This summer, the surface Navy issued a new readiness plan to reverse a well-documented erosion in standards, due in part to high operational tempo over the past decade. But, after a 1½-year-long audit of Navy records, the independent Government Accountability Office concluded the Navy's new plan is vulnerable to mission overload and budget cuts because the service's leaders haven't adequately accounted for these all-too-likely scenarios.

"The Navy has not undertaken a comprehensive assessment of the impact of high operational tempos, staffing shortages or any other risks it may face in implementing its new readiness strategy," the congressional investigatory agency wrote in a Sept. 21 report. "The strategy does not discuss, nor identify plans to mitigate, maintenance challenges that could arise from delays in full implementation."

These risks, the report continues, "could lead to continued deferrals of lifecycle maintenance, increasing costs and impacting the Navy's ability to achieve the expected service lives for its ships."

The GAO reported amphibious ships, on the whole, have more material problems that affect readiness than surface combatants, such as frigates and destroyers.

Responding to the report, the Defense Department countered that the Navy tracks ship readiness closely and that these risks — insufficient funding, mission load and emergency ship repairs — are largely beyond the Navy's control.

The surface Navy's readiness strategy and the budgeting process "adequately identify and mitigate risks," David Ahern, deputy assistant defense secretary for strategic and tactical systems, wrote in reply to the report.

Insufficient funding and constant institutional changes were two culprits behind the surface fleet's decadelong deterioration, an influential fleet review panel found in 2010. Surface leaders revamped the work-up cycle — which features a material inspection, a new shakedown period and pass-fail criteria required to advance from one phase to another — to resolve issues identified by the fleet review panel, whose most pressing finding was that some warships may not last as long as the Navy had hoped.

Funding remains a stumbling block. The surface Navy's get-well plan depends on boosting manpower at regional maintenance centers and afloat training groups — not to mention in ship crews. In July, personnel officials launched new incentives to fill nearly 10,000 open billets at sea. And much of the new maintenance and training regimen falls to ATGs and RMCs, which both told GAO they needed more staff to fully implement the new readiness strategy, expected to be fleetwide by 2015.

The 27-month cycle centers on a six-month deployment length. But officials have stressed that the plan is flexible and will accommodate the more frequent or longer cruises that are becoming more common. The plan also allows a ship deploying twice within one 27-month cycle to forgo a second maintenance period.

GAO contends that the Navy hasn't fully assessed the cumulative impact of stretching deployments and skipping overhauls, a road that the Navy has been down before.

"Without an understanding of the full range of risks to implementing its strategy and plans to mitigate them, the Navy is likely to continue to face the challenges it has encountered in the past," the report says.